Question

Predict the number of electrons, protons and neutrons in the two isotopes of magnesium with atomic number 12 and atomic weights 24 and 26.

Answer 1

Isotope of the atomic weight 24, i.e. ₁₂Mg²⁴. We know that 

No. of protons = No. of electrons = 12

Further, No. of neutrons = At. wt. - At No. 

= 24 - 12

= 12

Similarly, In isotope of the atomic weight 26, i.e. ₁₂M²⁶

No. of protons = No. of electrons = 12

No. of neutrons = 26 - 12 = 14